Reign 2×21 “The Siege” – As troops are about to descend on the castle, Mary (Adelaide Kane) and Francis (Toby Regbo) must put aside their differences to determine the extent of Condé’s (Sean Teale) betrayal. Mary also learns of a bittersweet revelation that tears her apart and makes her question everything. Meanwhile, Catherine (Megan Follows) decides to teach Narcisse (Craig Parker) a lesson to prove he can never cross her again and Bash (Torrance Coombs) decides to bring Delphine (guest star Alexandra Ordolis) to the castle. Caitlin Stasey, Anna Popplewell, Celina Sinden, Jonathan Keltz and Rose Williams also star. Andy Mikita directed the episode written by Adele Lim and Lisa Randolph (#221). Original airdate 5/7/2015.